φ Meson As a Probe of QCD Equation of State

In this work, we extract the QCD Equation of State (EoS) using experimental results of the $\phi$ meson produced in nuclear collisions at AGS, SPS and RHIC energies. The data are confronted to simple thermodynamic expectations and lattice results. The experimental data indicate a first order phase transition, with a mixed phase stretching energy density between $\sim$ 1 and 3.2 GeV/$fm^3$.